i am new to the Forum, so forgive me if have placed this out of place. i just got a set of the new RCBS small base Dies for the AR, and it seems that the expander is under sized. it measured .2215, i have talk to tech support and they seemed to be working on it. Has any one else had this problem? Just wondering if i just need to return them to Midway and get a set of dies from another company?

Tech support at Midway or RCBS? If RCBS, they will take care of the problem.

quote:

I just got a set of the new RCBS small base Dies for the AR, and it seems that the expander is under sized.

Is it a must to use SB Dies for the .223 in an AR?

I use standard dies, they work just fine.

In the AR and other gas guns with standard or milspec chambers it's best to use the RCBS regular X-die. The SB die is not needed, only a very tight match chamber needs SB dies. The X-die will give much longer case life than a regular type sizer, especially the SB ones. You also won't have to trim the cases.

With the X-die I even skip the 1st trimming as per the instructions. If new or once fired cases are used I mic 10 cases and pick the longest one. The case is lube and run into the die after the die body has been adjusted. The mandrel is then tightened down onto that case mouth. The other cases will then lengthn to that cases length and stop there.

If you're worried about case oal then s aimple chamber cast using parfin wax will show if the case are too long. I've not found that the case yet. I've X-dies for 8 different cartridges and haven't trimmed a case since I got them. Case life seems forever in the AR with .223s but in 7.62 I get 20+ firings per case.

Larry Gibson

Thanks for the replys. maybe i just return them to Midway and get a standard set of dies.

RCBS regular and small base dies in .223 are identical.

I know from a phone call and an email to/from RCBS that their carbide pistol expander plug has been redesigned and it's that great.

The next time you talk to them asked them if the plug for your die is a newly designed one.

Best of luck.

Back to the original question, what kind of problem were you having? I have several RCBS .223 dies and none of their expanding balls/buttons/etc. are the same, but all of them work perfectly.

Are you referring to the "AR" series of dies RCBS makes for progressive loaders or just a small base die set for .223/5.56?

Updated.
I checked all of my .224 dia. bullet dies and none of them were guite that small. I'd like to know what you find out on them, (like is this normal on their AR die sets?) as I was thinking about getting one for my 7.62X39s.